vmclock ABI: add snapshot safety features

Add support for vm_generation_counter and notifications.

Keep this separately for now, as a patch to the VMClock bindings, since
currently upstream bindings don't include it.

We will recreate this for Linux headers once they are released, at which
point we will need to drop the bindgen patch.

Signed-off-by: Babis Chalios <bchalios@amazon.es>

Author: bchalios

src/vmm/src/devices/acpi/generated/vmclock_abi.rs

@@ -38,6 +38,8 @@ pub const VMCLOCK_FLAG_PERIOD_MAXERROR_VALID: u64 = 16;
 pub const VMCLOCK_FLAG_TIME_ESTERROR_VALID: u64 = 32;
 pub const VMCLOCK_FLAG_TIME_MAXERROR_VALID: u64 = 64;
 pub const VMCLOCK_FLAG_TIME_MONOTONIC: u64 = 128;
+pub const VMCLOCK_FLAG_VM_GEN_COUNTER_PRESENT: u64 = 256;
+pub const VMCLOCK_FLAG_NOTIFICATION_PRESENT: u64 = 512;
 pub const VMCLOCK_STATUS_UNKNOWN: u8 = 0;
 pub const VMCLOCK_STATUS_INITIALIZING: u8 = 1;
 pub const VMCLOCK_STATUS_SYNCHRONIZED: u8 = 2;
@@ -153,10 +155,11 @@ pub struct vmclock_abi {
     pub time_frac_sec: __le64,
     pub time_esterror_nanosec: __le64,
     pub time_maxerror_nanosec: __le64,
+    pub vm_generation_counter: __le64,
 }
 #[allow(clippy::unnecessary_operation, clippy::identity_op)]
 const _: () = {
-    ["Size of vmclock_abi"][::std::mem::size_of::<vmclock_abi>() - 104usize];
+    ["Size of vmclock_abi"][::std::mem::size_of::<vmclock_abi>() - 112usize];
     ["Alignment of vmclock_abi"][::std::mem::align_of::<vmclock_abi>() - 8usize];
     ["Offset of field: vmclock_abi::magic"][::std::mem::offset_of!(vmclock_abi, magic) - 0usize];
     ["Offset of field: vmclock_abi::size"][::std::mem::offset_of!(vmclock_abi, size) - 4usize];
@@ -198,4 +201,6 @@ const _: () = {
         [::std::mem::offset_of!(vmclock_abi, time_esterror_nanosec) - 88usize];
     ["Offset of field: vmclock_abi::time_maxerror_nanosec"]
         [::std::mem::offset_of!(vmclock_abi, time_maxerror_nanosec) - 96usize];
+    ["Offset of field: vmclock_abi::vm_generation_counter"]
+        [::std::mem::offset_of!(vmclock_abi, vm_generation_counter) - 104usize];
 };

tools/bindgen-patches/0004-vmclock-notify.patch

@@ -0,0 +1,33 @@
+diff --git a/src/vmm/src/devices/acpi/generated/vmclock_abi.rs b/src/vmm/src/devices/acpi/generated/vmclock_abi.rs
+index 134c8393f..80228ad84 100644
+--- a/src/vmm/src/devices/acpi/generated/vmclock_abi.rs
++++ b/src/vmm/src/devices/acpi/generated/vmclock_abi.rs
+@@ -38,6 +38,8 @@ pub const VMCLOCK_FLAG_PERIOD_MAXERROR_VALID: u64 = 16;
+ pub const VMCLOCK_FLAG_TIME_ESTERROR_VALID: u64 = 32;
+ pub const VMCLOCK_FLAG_TIME_MAXERROR_VALID: u64 = 64;
+ pub const VMCLOCK_FLAG_TIME_MONOTONIC: u64 = 128;
++pub const VMCLOCK_FLAG_VM_GEN_COUNTER_PRESENT: u64 = 256;
++pub const VMCLOCK_FLAG_NOTIFICATION_PRESENT: u64 = 512;
+ pub const VMCLOCK_STATUS_UNKNOWN: u8 = 0;
+ pub const VMCLOCK_STATUS_INITIALIZING: u8 = 1;
+ pub const VMCLOCK_STATUS_SYNCHRONIZED: u8 = 2;
+@@ -153,10 +155,11 @@ pub struct vmclock_abi {
+     pub time_frac_sec: __le64,
+     pub time_esterror_nanosec: __le64,
+     pub time_maxerror_nanosec: __le64,
++    pub vm_generation_counter: __le64,
+ }
+ #[allow(clippy::unnecessary_operation, clippy::identity_op)]
+ const _: () = {
+-    ["Size of vmclock_abi"][::std::mem::size_of::<vmclock_abi>() - 104usize];
++    ["Size of vmclock_abi"][::std::mem::size_of::<vmclock_abi>() - 112usize];
+     ["Alignment of vmclock_abi"][::std::mem::align_of::<vmclock_abi>() - 8usize];
+     ["Offset of field: vmclock_abi::magic"][::std::mem::offset_of!(vmclock_abi, magic) - 0usize];
+     ["Offset of field: vmclock_abi::size"][::std::mem::offset_of!(vmclock_abi, size) - 4usize];
+@@ -198,4 +201,6 @@ const _: () = {
+         [::std::mem::offset_of!(vmclock_abi, time_esterror_nanosec) - 88usize];
+     ["Offset of field: vmclock_abi::time_maxerror_nanosec"]
+         [::std::mem::offset_of!(vmclock_abi, time_maxerror_nanosec) - 96usize];
++    ["Offset of field: vmclock_abi::vm_generation_counter"]
++        [::std::mem::offset_of!(vmclock_abi, vm_generation_counter) - 104usize];
+ };